It is known to use inkjet printing technology to apply droplets of a recording liquid such as an ink image-wise on a recording medium to form an image on the recording medium. Such recording medium may be paper or may be any other suitable recording medium.
For certain applications, the recording medium may be such that common inks such as water-based inks are not suited and it is well known to use for such applications curable inks, in particular curable by irradiation of a suitable radiation. A commonly used radiation for curing is UV-radiation.
The curable recording liquids are applied in droplets by ejection from an inkjet print head and stay in a liquid-phase after application on the recording medium. The droplets may spread and even coalesce with neighboring droplets, depending on the particular properties of the recording liquid and/or recording medium, while they are in such liquid phase. After a predetermined period of time after application, the droplets are cured by irradiation of a suitable radiation. The irradiation may be controlled based on an amount of radiation per unit of time and a duration of irradiation, thus by controlling a total dose of radiation. After curing the recording liquid adheres to the recording medium and has solidified.
A disadvantage of the known method of application is that the resulting gloss level (i.e. a high gloss, low gloss or matt finish) depends on the properties of the recording medium and/or the properties of the recoding liquid and/or other properties such as printing parameters, including but not limited to a recording liquid temperature at the time of application. Controlling such properties and related control parameters to obtain a controlled gloss level is difficult and even unpredictable, requiring trial and error to obtain a desired gloss level. Such trial and error is of course undesirable.
Moreover, the recording liquid may be a translucent or transparent recording liquid, such as a varnish. Such recording liquid may be applied with the intention to generate a high gloss. Using such recording liquid, it is desirable that the resulting gloss level is independent from the recording medium.